I only want one for heart gold and soul silver. Will I need A newer version of the DS? like the DSI or DSIXL(Is that real idk anything about the DS)

I will only play Those two games, and maybe a castlevania game or two.

You can get any ds to play those games.

this

I've heard that the XL was better for the 3D (just on screen 3D that is) games, not the 2D games. If I were looking into buying one right now I'd go with the DSi (because I'm fascinated by FlipNote Studio) or wait for the 3DS which should have upgraded graphics for the games specifically made for it.

DSi XL or DSi, so you can get DSiware games :D Get spirit tracks and Mario & Luigi Bowsers inside story.

Okay, I will get a regular DS then. I am saving my money for a PSP or PSP2(I want the FFT remake and God of war.) DS I just want pokemon gold and silver(remakes of the best in the series IMO)

Only Pokemon? Come on dude.

Can someone explain to me what is a 3DS, is just a complimetary addition to the branching DS family. Or something new entirely?

Something new entirely. It's the next generation console. VGChartz has been assploding about it.

I'm not exactly sure if I would call it a new console entirely YET.
Right now it seems like just an upgraded version of the DSi. It even has the "DS" attached to it. Hopefully at E3 we will see what sets it apart even more from the DS's